6th International Symposium on Soil Organic Matter

Session 2a: Soil self-organisation

Chair: John Crawford (Rothamsted Research, UK)

Soil is the most complex and functionally important component of the terrestrial ecosystem. It is responsible for bringing together the biochemical processes that break down the chemical complexity of organic compounds into the simple nutritional forms required for primary production. It provides a physical environment in which these biochemical processes are spatially organised and in which water and air can coexist to promote these processes across an extraordinarily wide range of environments. Finally, it provides the solute and gaseous pathways to convey the resulting nutrients (including water) from the soil reservoir to plant roots. This requires an extraordinary level of organisation of physical and biological processes across scales ranging from the smallest pores that hold water against the pull of gravity and provide the microbial microenvironment, to the landscape.We lack a theory of soil that accounts for the origin and maintenance of this biophysical organisation, and this is a major impediment to managing the soil system more sustainably. Too much of the science we do treats soil as a static system and considers the physical, biological and chemical processes in isolation of one another. It can be hard to generalise. This is hardly surprising because the system is so complex, and the reductionist paradigm requires we break the system up into understandable components. However, when the physical, biological and chemical components are so highly integrated, it is impossible to optimise the system by optimising the components in isolation.This session is designed to promote and advocate for a more systems view of soil. It aims to showcase different approaches to embracing the complexity of soil, and demonstrate the new insights that can be gained. It will explore the capacity of soil to self-organise, and to understand how this capacity can be maintained, lost and regained. It highlights the fundamental importance of SOM in orchestrating the dynamics of soil and aims to draw together the science that could be synthesized towards a more fundamental and generalizable theory of soil.